How many 80 lbs bags of cement to do a 12 ft by 8 inch wall?
You're missing a dimension... 8 ft. thick by 12 ft. long by (?) ft. tall? Volume requires 3 dimensions. Edit: Based on your inability to comprehend the basic spatial nature of our universe, I recommend that you never work with concrete... You'll probably hurt yourself.
You want to use concrete mix, not cement. If by cement you mean Portland cement, you need to know that this is but one ingredient in concrete. Portland cement by itself would be a disaster. However, in this case you are missing a dimension for the height of the wall, if i assume the 8 is the thickness. You need to calculate the total volume of the wall before you can figure this. An 80-lb bag of concrete mix will fill approximately 2/3 cu foot.
